Virtualization allows multiplexing of the underlying host machine between different virtual machines. The host computer allocates a certain amount of its resources to each of the virtual machines. Each virtual machine is then able to use the allocated resources to execute applications, including operating systems (referred to as guest operating systems). The software layer providing the virtualization is commonly referred to as a hypervisor and is also known as a virtual machine monitor (VMM), a kernel-based hypervisor or a host operating system. The hypervisor emulates the underlying hardware of the host computer, making the use of the virtual machine transparent to the guest operating system and the user of the computer.
The virtualization technologies have wide applications in the computer field with the development of computer systems. For example, such virtualization technologies can be used to implement a virtual desktop application which runs within a virtual machine of a host and accessed from a client over a network.
In a large organization, thousands of virtual machines can be run on one or more hosts, making it very difficult for a system administrator to manage the virtual machines. One existing solution employs a host controller that monitors the operation of the virtual machines and allows an IT administrator to add a new virtual machine, delete an existing virtual machine, migrate a virtual machine to a different host, or perform any other action based on up-to-date information provided by the host controller. The up-to-date information for the virtual machine system can be displayed to a user (e.g., an IT administrator) on the user's client machine via a graphical user interface (GUI). Usually, the information in the GUI is updated in response to frequent requests sent from the client to the host controller. However, this approach creates network-related problems in a system with a limited bandwidth such as a virtual desktop system or the like.